This invention relates to surgical instruments for removing soft or hard tissue from a body. In particular, the invention relates to endoscopic surgical instruments, including those for use in arthroscopy.
Endoscopic surgical instruments typically include an outer tubular shaft that extends from a hub and receives an inner tubular shaft which is rotated or otherwise moved by a motor. A cutting implement such as a blade or burr attached to the distal end of the inner shaft is exposed to tissue through an opening in the distal end of the outer shaft. Tissue severed by the cutting implement and irrigating fluid present at the surgical site are drawn into the interior of the inner shaft by suction for withdrawal from the body.
Some endoscopic surgical instruments are straight; in other, curved instruments, the outer shaft is bent between its proximal and distal ends to offset the cutting implement with respect to the longitudinal axis of the instrument. The inner shaft is flexible within the bend region allow it to transmit force through the curve and operate the cutting implement. The outer shaft of many curved surgical instruments is rigid, and thus imposes a fixed direction and amount of curvature. Alternatively, the outer shaft may be flexible so that the user can impose variable curvatures by grasping the hub and outer shaft and bending the outer shaft by a selected amount.